| 摘要 |
PROBLEM TO BE SOLVED: To enhance the ultrasonic welding strength of a gold plating layer and a metal wire such as a gold wire. SOLUTION: In the printed circuit board for electrically connecting a metal lead formed on the board and the electrode of a semiconductor chip mounted on the board by using the metal wire, a nickel plating layer and the gold plating layer are formed on the metal surface of the base material of a metal lead formed on the printed circuit board in this order, and the plating thickness of the gold plating layer to the total average plating thickness of the nickel plating layer and the gold plating layer is 1/2 or more. |
